Organization and Operations (Details) people in Thousands	12 Months Ended
	Dec. 31, 2021 mi² serviceConnection people entity community subsidiary	Dec. 17, 2021 mi² serviceConnection people
Public Utilities, General Disclosures [Line Items]
Number of variable interest entities | entity	2
Revenue Benchmark | Product Concentration Risk | Water
Public Utilities, General Disclosures [Line Items]
Percentage of revenue derived from sales of water to business and residential customers	92.00%
SJWC
Public Utilities, General Disclosures [Line Items]
Number of subsidiaries that are primary beneficiaries | subsidiary	2
Service connections	231,000
Number of people served | people	1,000,000,000
CTWS
Public Utilities, General Disclosures [Line Items]
Number of people served | people	456
Number of communities served | community	81
CTWS | Connecticut and Maine
Public Utilities, General Disclosures [Line Items]
Service connections	140,000
CTWS | Connecticut
Public Utilities, General Disclosures [Line Items]
Service connections	3,000
CLWSC
Public Utilities, General Disclosures [Line Items]
Service connections	24,000
Number of people served | people	70
CLWSC | Kendall West Utility and Bandera East Utility
Public Utilities, General Disclosures [Line Items]
Number of people served from acquisition | people		5
Service area from acquisition | mi²		19
CLWSC | Minimum
Public Utilities, General Disclosures [Line Items]
Service area in square miles | mi²	266
CLWSC | South Central Texas | Kendall West Utility and Bandera East Utility
Public Utilities, General Disclosures [Line Items]
Number of service connections from acquisition		1,600
Acequia Water Supply Corporation
Public Utilities, General Disclosures [Line Items]
Ownership percentage in Acequia Water Supply Corporation	25.00%